The subject invention relates to valves. More specifically, the invention relates to check valves for use in controlling flow of fluids.
A variety of different valves have been developed for controlling fluid flow through pipelines. Most valves, regardless of type, comprise a housing member that supports a flow control mechanism within a chamber in the housing. The housing typically has two or more ports that are constructed for attachment to corresponding portions of pipelines. Some ports are provided with threaded connections, while others utilize a “slip fit” connection wherein a section of pipeline is slidably received in a socket formed in the valve housing. In such cases, the pipe is typically retained within the socket by an appropriate adhesive or means for attachment, such as welding, soldering, gluing, or mechanical attachment etc.
The flow control characteristics afforded by a valve are generally dependent upon the type of flow control member employed. In many pipeline applications, it is desirable to utilize valves that permit fluid to flow in only a single direction. In those instances, valves known as “check valves” are usually employed. Check valves are employed in a variety of residential and industrial applications where such unidirectional flow characteristics are desirable, such as with swimming pools, spas, outdoor water features and the like.
A number of differently configured check valves exist for maintaining unidirectional fluid flow within a pipeline system. One type of check valve, known as a “ball” check valve, employs a ball-shaped flow control member that is movably supported within the valve housing and is adapted to sealingly engage a seat adjacent to one of the ports. When fluid flows into the valve housing in one direction, the ball is forced out of contact with the seat and the fluid is permitted to pass through the valve. If the fluid attempts to flow through the valve in an opposite direction, the fluid forces the ball into contact with the seat to thereby prevent the fluid from flowing back through the valve.
Another type of check valve, known as a “swing” check valve employs a disc, or flapper, that is pivotally attached to the valve housing and is adapted to sealingly engage a valve seat that surrounds one of the valve ports. When fluid flows through the housing in a desired direction, the disc is forced out of contact with the seat by the fluid and the fluid is permitted to flow through the valve. Should the fluid attempt to flow back through the valve, however, the back-flowing fluid will pivot the disc into contact with the seat to seal off that port in a closed configuration. Thus, the fluid is prevented from flowing in reverse direction through the valve. Typically, in such cases, the disc is biased to the closed configuration by gravity, or by a metal spring. Both are prone to problems in that gravity may not provide a sufficiently strong bias toward the closed configuration, and where a metal spring is introduced problems of deterioration due to corrosion are typically not far behind.
Furthermore, while such valves can effectively limit flow to a single direction through a pipeline, such prior check valve designs have various additional shortcomings. For example, such prior check do not conveniently allow a user to restrict the amount of forward flow that such a valve will permit. Rather, where it is desired to place a restriction on the amount of forward flow that such a valve will permit, it may be necessary to install a shut-off valve in series with the check valve. This solution has the disadvantage of requiring additional labor, additional space for the serial plumbing installation, and additional cost for a separate shut-off valve.
Thus, there is a need for a check valve that may address shortcomings in the prior art. The flow control device of the present invention addresses these and other needs.